1. Field of the Invention
The present invention relates to an ink jet printer head featuring the use of a piezoelectric thin film as a drive source for ink discharge, and to a method for manufacturing the same.
2. Description of the Related Art
Examples of electromechanical transducer elements serving as a drive source for liquid or ink discharge include piezoelectric ink jet printer heads featuring the use of a piezoelectric thin film consisting of PZT. Such a printer head can be manufactured by the following process, for example, using an etching technique.
A silicon thermal oxide film, a common electrode serving as an vibrating plate, a piezoelectric thin film, and a top electrode are formed, in that sequence, on a silicon substrate which is to be used as the ink jet base. The piezoelectric thin film and top electrode are then patterned using a negative resist, and a piezoelectric element is thus formed by means of the common electrode, piezoelectric thin film, and top electrode. Anisotropic etching of the underside of the head base (the side opposite where the piezoelectric thin film is formed) results in the formation of 0.1 mm wide ink pressure generating chambers, ink supply channels that supply ink to the ink pressure generating chambers, and an ink reservoir that is connected to the ink supply channels; and a nozzle plate is connected, in which nozzle holes have been formed to discharge the ink to locations corresponding to the ink pressure generating chambers.
However, the process for forming patterns including such a piezoelectric thin film on an ink jet base is carried out at elevated temperatures, resulting in the need for quartz glass as well as a silicon substrate with excellent heat resistance for the ink jet base.
Such silicon substrates and quartz glass are scarce and extremely expensive materials, however, and they are also brittle and quite susceptible to cracking. This results in poor manufacturing yields and higher costs.
There has also been recent demand for more precise formation of ink jet nozzle holes to achieve higher density in the dot patterns of ink jet printer heads, but it has been difficult for the following reasons to manufacture nozzle plates in conventional methods in order to meet such demand. Conventionally, SUS plates with a thickness t of 100 to 60 .mu.m have been punched to make holes. Fine holes not only make the punching process more difficult, and also result in a lower punch life.